Although it may be useful in the disposal of solid waste materials, the invention was made in connection with attempts to more effectively dispose of liquid waste materials, and will therefore be described in connection with such use.
How to safely dispose of agricultural and industrial hazardous liquid wastes, including toxic chemicals and flammable liquids, is of increasing environmental concern. Handling of such materials is hazardous, and the cleaning up of any accidental spillage can be painstaking and expensive. When removed from the place of their generation they cannot be simply dumped at disposal sites on land or at sea without danger of seepage pollution of underground aquifers or of poisoning sea life, and their burial in containers is costly and poses similar risks. Moreover, incinerating of such wastes has caused atmospheric pollution, sometimes resulting in "acid rain" at locations far from the burnsite.
In the context of this specification, "liquid" waste material includes not only liquids which are flowable by gravity, but also pumpable sludges, and materials which are similarly flowable or pumpable upon heating. Such materials, including non-flammable materials, are known to be incineratable in incinerators having liquid fuel burners, either by feeding the material directly into the burner or upon blending it with a fuel such as diesel oil immediately before, or simultaneous with its introduction into the burner. Modern, controlled high temperature incinerators are highly efficient, and are effective to destroy 99.99 percent of such wastes. Atsea incineration is advantageous in that it removes the destruction site from populated areas.
In view of this apparent advantage of shipboard incineration, in February, 1980 a work group formed of representatives from several governmental agencies undertook a study of known incineration operations, safety and control measures, environmental impacts, waterfront facilities, and conceptual designs for incinerator ships. In September, 1980, the work group issued an initial report entitled, "Report of the Interagency Ad Hoc Work Group for the Chemical Waste Incinerator Ship Program", in which it concluded that chemical hazardous waste incineration at sea is a cost-effective, technically efficient, and environmentally acceptable manner of destroying many hazardous wastes. The work group was expanded and became known as the "Interagency Review Board for the Chemical Waste Incinerator Ship Program". It presented its findings from further studies of important ship design factors, including regulatory requirements, incinerator technologies, and the like, in September, 1981 in a report entitled, "Chemical Waste Incinerator Ships--The Interagency Program to Develop a Capability in the United States". The report includes a conceptual design for an incinerator ship that can incinerate both liquid wastes and solid wastes, and discusses waterfront facilities as may be required for such incinerator ship operations.
As mentioned in that report, several officially-sanctioned shipboard test incineration operations were successfully conducted on the incinerator ship M/T VULCANUS off the coast of the United States. This ship was especially designed for the incineration of liquid chemical waste at sea, which it carries to the offshore burnsite in 15 cargo tanks below decks. The ship was designed in accordance with the latest regulations of the International Maritime Organization (IMO) and other regulatory bodies. The cargo is loaded by pumping the material through pipelines and hoses into the ship's cargo hold from large storage tanks at the waterfront facility where the ship docks, and the liquid waste material is often blended together, either in the storage tanks or in the ship's cargo holds. The ship sails to the burnsite location many miles off shore, at which the cargo is pumped from the storage tanks into two large liquid injection incinerators having vertical stacks.
The conceptual ship design offered by the Interagency Review Board is similar to the M/T VULCANUS in that, like a tanker, the liquid waste cargo is carried in the ship's cargo tanks, or built-in tanks below decks, and is pumped to any of three (instead of two) similar liquid injection incinerators having vertical stacks. However, the conceptual design also provides for the carrying of solid hazardous wastes in containers which are initially stored on deck, and which are transported via a transporter cart to a rotary kiln incinerator into which the solid waste from the containers is dumped and incinerated. The products of incineration from the rotary kiln are fed into one of the liquid injection incinerators.